This invention relates to a device for the detection of microorganisms in a body fluid sample. More particularly, this invention relates to a device containing at least one solid medium in combination with a connection for the device to a liquid medium culture bottle or container. The device provides for proper exposure of the two media (solid and liquid) to the sample under investigation while at the same time providing complete noncovered access to the solid media during the growth period for taking samples or close examination.
With the device of the invention, once the microorganisms begin growth, they may be examined directly without any glass or plastic covering interfering with the examination. Alternatively, they may be examined in their entirety through the transparent covering forming the access entry to the device of the invention.
In the detection of microorganisms in body fluids, particularly bacteria in blood, there is a requirement that a sample of the fluid be used to inoculate a liquid nutrient medium. Subsequent to this, the liquid medium is, after incubation, in turn, used to inoculate one or more solid media to obtain colony growth of the organisms. Generally, devices have been provided in which both the liquid and the solid culture media are combined in the same container. This overcomes any problems involving exposure during transfer of these cultures in the liquid medium to the solid culture medium in another container. Representative of such devices is that described in U.S. Pat. No. 3,589,983, issued June 29, 1981. Other patents directed to the subject matter of the invention include U.S. Pat. No. 3,651,926, issued Mar. 28, 1972; U.S. Pat. No. 4,308,347, issued Dec. 29, 1981; and U.S. Pat. No. 4,678,753, issued July 7, 1987.
There are problems, however, with combined devices in that the constituents of the solid medium may be dissolved in the liquid medium. Thus, only solid media compatible with the liquid medium can be utilized. If the solid media constituents pass into the liquid medium, differentiations of the pathogens may no longer be possible.
With the present invention, the solid medium and the liquid medium are appropriately separated, but may be connected together in order to provide the proper exposure of the solid medium, or media, to the liquid medium containing the sample under consideration. Nevertheless, once the colony growth period has taken place, the device of the invention may be disassembled to the extent whereby the solid media plates may be examined completely and directly without any interference from a covering therefor. Alternatively, with the invention here, a magnifying cover is provided as an alternative for a close examination without direct access or exposure to the solid media under consideration.
That is, the device of the invention includes a main structure supporting one or more solid media. This structure includes a connection for connecting the main or base structure to a liquid culture medium container. The main base structure carrying the solid media may be generally cylindrical with one solid wall for supporting the solid medium and the opposite wall thereof being in the form of a transparent screw cap with a liquid tight connection so that once the sample has been introduced into the liquid medium container, the device of the invention may be connected thereto and the solid medium may be exposed to the liquid medium containing the sample of interest.
The exposure is only intermittent, as required and desired, in order to provide the appropriate culture development during the incubation or colony growth period of the inoculated solid media present in the device of the invention. Because of the large cap which is transparent, the growth character may be examined throughout the incubation period either by the examination indirectly through the transparent cap, or by removal of the cap for direct examination and sampling of the various media plates supported on the device of the invention. Once the incubation period has taken place, the cap of the device may be removed so that the entire solid media with the cultured organisms present thereon may be exposed for examination by the laboratory technician.
Again, during the examination period, if the embodiment utilizing the magnifying lens on the cap of the invention is used, the character of the growth during the incubation period may be carefully examined without any opening of the container containing the solid medium. In this way, exposure to contamination is reduced, as will be understood. Moreover, there is less likely to be an inadvertent contamination of the specimen under consideration with the arrangement herein.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims.